Pump unloading mechanism



SGP'- 2,1941, N. E.-BR|GHAM ETAL 2,254,834

PUMP uNLoAbmG MECHANIsM Filed oct. 5, 1940 6 Sheets-sheet 1 v Inse h EHul'veck lv Tons.V

ATTORNEY Srept. 2, 1941. -'N. E. BRIGHAM Er-AL PUMP UNLOADTNGMECHANISM Filed oct. 5, i940 Saleem-sheet 2 rhI/I l ORS Nelsnn E Elnqharn Juaph EHEIM/Eck ATTORNEY A Sept. 2-, 1941. NfEf BRIGHAM Erm. 2,254,884 Y PUMP UNLOADING MECHANISM n' Filed oct. 5, 1940 6 sheets-sheet 5 ATvroRNi-:Y

Sept. 2, 1941.l N.A E. BRIGHAMv ETAL PUMP" [JN-LOADING MEcHANIsM Filed oct. 5, 1940 e sheds-'sheet 6 Nelson E. E'lriqliram` l Jpaeph E. Hub/eck INvE Tons f ATTORNEY patented sept..2,1941

PUMP uNLoAnmG MEcnAmsM Nelson E. Brigham, Kearny, N. J., and Joseph E.

Holveck, Grafton, Pa., assignors to Worthington Pump and Machinery Corporation, Harrison,

N. J., a 'corporation of Delaware Application october s, 1940, serial No. 359,874

` (orina-37) 17 Claims.

This invention relates to a loading and unloadingmechan'ism for positive displacement pumps, andan object of the invention is to provide a simple, positive acting mans for controlling a positive displacement or reciprocating pump, Aof

Vany type, which will provide synchronization of all of the cylinders of the pump in unloading and loading, regardless of the point in pumpr revolution when the control functions;

In practically all pumping. applications involving .a pressure fluid for operating hydraulic 'machinery the demand for iluid power medium has any of a number of iow conditions, all 'of which require intermittent operation of` the pump. Consequently the pump operates loaded to full .capacityfor a given time, and at zero `ca,-

- pacity for another given time. The relation between the length of loaded and unloaded time cycles depends upon the type of rate of flow, the flow demand at a given time, the accumulator capacity, and the capacity of the` pump.

The present invention provides asynchronized loading and unloading mechanism capable ot meeting any and all demand conditions, in an installation as above referred to, where power driven reciprocating-pumps are employed. It involves a control for such pumps which, when operating continuously and at constant speed.

plunger are kept open by an interference placed under each valve during the suction stroke of each plunger, causing the valves to become inoperative and resulting in each plunger remaining unloaded at the end of its preceding discharge stroke. During the unloading cycle, the pump discharge valves hold the pressure fluid, and each suction displacement is returned back into the suction chamber.

- .l During the unloading cycle, the pump operates provides a quick but gradual decelerating uid iiow from full to zero flow in not more than` onehalf revolution of the pump, and a quick but gradual accelerating fluid delivery from zero to full ow `in not more than one-half revolution of the pump, i. loading. l,

The vdischarge flow from a positive displacement multi-plunger reciprocating pump is made up of a consecutive series of equal pulsations', or

plunger displacements, comprising a smooth resultant delivery. Each plunger displacement, due to crank action, is forced into the pressure line with anincreasing rate of ow from zero to maximum, an d continuing with a corresponding diminishingrate of ow from maximum to zero through'l80 degreesof crank motion.

Placing interference under'the suction valve during the suction stroke causes the.pump to unload in such a mannerthat the interruption ofv the pump action at the end of a .loaded cycle is a gradual .deceleration of iiuid delivery and power input from full to zero, coinciding with the diminishing rate of ow` of the last plunger displacement into the pressure line.y 'This and inherent characteristic eliminates shock.

To bring this about, the vsuction valves of .each-I 55' e. synchronized unloading and basic only on suction; pressure, and no work is being` done bythe pump. The power required when unloaded needonly be sufdcient to overcome the' mechanical friction of the pump. L

Removing interference from' under the suction valve causes the pump to load in such a manner that the resumption of the pump action at thebeginning of a loaded cycle is a gradual acceleration of uid delivery and power input from zero to full, coinciding with the increasing rate of iow of the irst plunger displacement into the pressure line. -This basic and inherent charac-4 teristic eliminates shock.. To bring this about, the interference is removed from under each suction valve during the suction stroke of each plunger, causing the valves to become operative, and resulting in each plunger being loaded at the beginning of its discharge stroke. e

Other objects i provide a loading and unloading mechanism which will provide shockless unloading and loading-of the pump, minimum power loss when the pump is unloaded, no loss of pressure uid when the pump is unloaded, and one which eliminates shocks to and wear upon the equipment per` mitting the pump to be unloaded and loaded with a'ny degree'oi' frequency.

With these and other objects appear from the accompanying specication, the invention consists 1 of various features of construction and combination of parts, which will `be iirst describedin connection with the accompanying drawings, showing a pump unloading vmechanism of the preferred form embodying the inventiomand the features forming the invention will Ibe specically pointedI out in' the claims. In the drawings: Figure 1 is a top plamof the improved unloadingand loading meclrianism` showing it in connection' with a pump.

' Figure 2'is aside elevation of a pump :showing the improved unloading and loading mechanism applied thereto.

oi the present invention are -to in view, as may l Figure 3-is` a fragmentary longitudinal se'ction through a pump showing parts of the unloading and loading mechanism applied, and taken on the line 3-3 of Figure 1.

. in the control mechanism.

Figure 8 is a section taken on the line 8--8 of Figure '1. v

Figure 9 is a lay-cut development of the cam shown in Figure 7.

Figure 10 is a perspective view oi' a control switch employed in the control mechanism.

Figure 11 is a vertical section through the switch shown in Figure 10.

Figure 12 is a perspective view of a pressure uid distributor valve and its operating mechanism which controls the delivery of operating pressure uid to the pump valve actuating mechanism.

Figure 13 is a diagrammatic view of the electrical circuits embodied in the control and distributor mechanism of the device.

Referring more paiticularly to the drawings, a double-acting positive-displacement pump of the reciprocating type is shown in Figures 1 and 2 of the drawings, embodying cylinders I, each having opposed bores 2 and 3 therein in which the plunger pistons 4 and 5 reciprocate.

The plungers 4 andi are reciprocated from any suitable type of prime mover (not shown) through the medium of the crank shaft 6, which is connected to the plungers by suitable connecting rods, guide rods and cross-heads 1, 8 and 9, in the usual manner of constructing pumps of this type. Y

Each of the cylinders is provided with a fluid Ainlet passage I0, opening through inlet valve structures II into the bores 2 and 3 respectively. The cylinders are eachprovided with approved types of discharge valves I2. The present invention does not relate to any specific type of construction of pump but embraces a synchronized loading and unloading mechanism for automatically controlling the loading and unloading of a pump in response to pressure fluid demand. v

The pump cylinders are unloaded by the holding open ot the suction valves II, and are loaded by the release of the suction valves from the unloading orholding open mechanism, so as to permit them to operate in their'usual manner.

The valve operating mechanism for holding the suction-or inlet valves openl to unload the pump is shown in detail in Figure 6 of the drawings, and includes a rod I4 extending into the cylinder I and not attached to, but engaging the skirt I of the suction valve II.` The rod I4 is attached to apiston I6, mounted for reciprocatory movement in a cylinder I1.- A stem I3 engages the piston structure I6 and is urged upwardly or inwardly to move the piston I6 upi wardly in the cylinder I1 by a spring I9 so that when the piston I6 is relieved from the action of pressure fluid against its inner side the spring ting spring so as to hold the valve- Il open, consequently causing the pump to operate unloaded. lThe cylinder I1 has an inlet 2l thereto for pressure fluid. Pressure iiuid, entering the cylinder I1, forces the piston I6 outwardly against the tension of the spring I9 and moves the rod I4 out of position'for holding the valve II open, thereby permitting the inlet or suction valve Il to operate in its normal. manner and the pump to operate loaded.

Pressure iiuid for actuating the piston I 6 is provided from any outside source (not shown), such as the compressed air line or system of a plant in which the pump is. employed. Distribution of pressure uid to the cylinders I1 is controlled by a series of solenoid actuated, three-way valve structures 22, which are of any approved construction that may be purchased upon the open cuit with the solenoids 23', and each includes a market. These .three-way valve structures are constructed so that when their solenoid structures, generically indicated at 23, are energized, the valves will be in position -to permit the ilow of pressure iiuid. from the supply source to' the cylinders I1, permitting the pump cylinder controlled by the respective solenoid valve to be loaded. When the solenoid 23 lede-energized, the three-way valve structure 22 will permit the bleeding of the pressure fluid from the Acylinder I1 to allow the spring I9- to act to unload the 're-- spective pump cylinder. As shown in Figure 1 of the drawings, one of the solenoid actuated` three-way valve structures is provided for each of the suction valves of the pump. As previous- 1y stated, the pressure fluid for actuating the pistons I6 may be derived from any suitable` source, and hows to the battery of three-'way valve structures-22 through a supply line 24.

The energizing of the solenoids 23 of the various three-way valve structures 22 is controlled by the distributor structure 30, which is operated from the crank shaft 6 of the pump by a suitable power transmission mechanism, indicated at 3I. The distributor control mechanism 30 includes a suitable housing 33, in which are mounted a plurality of switch structures 34, one for each of the solenoid actuated three-way valves 22. These switch structures are of an' approved type which may be purchased upon the open market, but they are, however, shown in detail in Figures 10 and 11 of the drawings.

'I'he switch structures 34 are connected in cirrocker arm 35 controlling the opening and closing of the circuit through the switch and consequently through the solenoid 23 connectedw I 'the respective switch 34. The rocker arms 35 are -each connected to a pivotally mounted actuating arm 36, which arm ispositioned exteriorly of the casing 31 of the switch and has a camengaging roller 38 on its outer free end. The actuating arms 3B are pivotally supported from the housing 31 and when in an upward position-as shown in solid lines in Figure 5 of the drawings Y actuate the switch structures to close' the circuit through the solenoids 23, to .in turn operate the three-way valves 22 permitting the pressure uid to be delivered to the cylinders. for operating the pistons I6, to permit theF pump to operate in loaded condition.

The dlstributor'control 30 has a solenoid 40,

of approved construction, mounted therein which I3 will urge the piston inwardly or upwardly,

is connected in circuit with a pressure governor, (not shown), or limit switches, (not shown), which may be associated with the pump structure. A plunger shaft 4I is connected to the core of aars-raseX bearings 42 and 43, upon the energizing or deenergizing of the solenoid. That is, when the solenoid is energized', and the core 44 thereof is .drawn upwardly, the shaft 4| will move upwardly; and upon ele-energizing of the solenoid 40 the core 44 and shaft 4| will drop or move downwardly, such downward movement being augmented by means of the spring 45. The lower end of the shaft 4| extends into a socket or pocket 45', which receives oil through an opening 48. The shaft 4| is provided with a longitudinal bore 41 and with lateral extending openings 48, so that when the shaft 4| moves downwardly lubricating oil will be forced upwardly through the bore 41 of the shaft and through the openings 48 for lubricating the working parts of the control. The socket 45', containing oil, also acts as a dash-pot to cushion the downward movement of the shaft 4| and the mechanism carried thereby.

The shaft 4| has a cam structure 49 rotatably mounted thereon and held in place on the shaft by means of the collar 50-and the shoulder 5| so that the cam will move vertically with movement of the shaft. The cam 49'has a pinion 52 keyed thereto which meshes with a worm gear 53 mounted on a suitable shaft 54.A The 3 out of the cylinders |1 the springs will act-to move the piston I6 and rod I4 upwardlyduring thev suction stroke, thereby preventing the `suotion valves of the various'pump cylinders from functioning and causing the pump 'cylinders to operate in an unloaded condition, thus unloading 'the pump in synchronization with the rotation of the crankshaft 6; that is, unloading thepump in synchronization with the movement ofthe plungers at the end of each discharge stroke.

' As previously stated,- the energizing and deenergizing of the solenoid 40 may be controlled by a pressure governor, limit switches, vor' any other suitable control apparatua'dependin'g upon" shaft 54 is connected in any suitable manner with the transmission mechanism 3| so that the worm gear 53, and consequently the cam 49, will be rotated in synchronismgwith the rotation of the .crank shaft 6 of the pump structure.

The cam 49' has upper. and lower annular flanges 55 and 5B, respectively, formed thereon providing facing cam surfaces 51 and 58, each of which has a riser.59 formed thereon at theproper-,point about its circumference. The risers '59' are provided for engagement with the rollers 38 to actuate the pivoted switch operating arms 36 during the suction stroke of the respective plungers.

When thesolenoid 40 is energized and the shaft 4| drawn upwardly, the riser 59 on the lower cam 58 will engage the rollers 38 at the proper times during the rotation of the cam 49 to move the levers 36 upwardly and close the circuits through the Various solenoids 23 which are connected in circuitv with the respective switches 34, during the suction stroke of their respective plungers. As each solenoid 23 is energized in its proper sequence, the pump cylinder with which it and its three-way valve are asso.

the use to which the pump is to be put, so as to load and unload the pump in -accordance with `the load demand, at specified time intervals or to suit any of a number of conditions which may exist in various types of installations in which the pumpis employed. 'I'he present invention does not embody any specific control means for` controlling this action.

It will be understood that the invention is not Y' 4to be limited to the specific construction or arrangement of parts shown, but that they may' be widely modified within the invention dencd by the claims.

What is claimed is: y 1. In a pump loading and unloading mecha'- nism, in combination with a pump including a cylinder and a reciprocating plunger therein, of a valve for controlling the loading and unloading of the cylinder, a pressure actuated member for operating said valve, electrically operated means controlling delivery of pressure l fluid to said pressure actuated member, a con-- trol member controlling energizing of said electrically operated means, and means connecting `said control member to said plunger for synchronize'd operation therewith for timing the `valve actuating operation of said pressure ax:-

tuated member.

2. In' a pump loading and unloading mechanism, in combination with a pump including a cylinder and a reciprocating plunger'therefor,

and an intake valve for said cylinder,of a pres- Vsure Aactuated member acting upon said intake shaft 4|, and consequently the cam 49, will move downwardly, moving the risers of the cam surface 51 into position for intermittent engagevalve to control unloading of the pump, electrically operated means controlling delivery of actuating pressure fluid to said member, and a control memberv connected to and actuated insynchronism with said plunger for controlling energizing of said electrically operated means.

3. In a pump. loading and unloading mechanism, the combination with apump including a cylinder anda plunger therein, and an intake valve for said cylinder, of a pressure actuated member normally holding said 4intale valve in cylinder unloading position and operated by pressure iiuid to permit seating of said suction valve to load said pump, a valve controlling delivery of pressure iiuid to said pressure actuated member, electrical means for actuating said valve, means for moving said pressure actuated member into valve unseating position upon the release of pressure fluid from said pressure actuated means. a distributor controlling the ener'- gizing of said electrical meansfor controlling the delivery of pressure fluid to`and-the `release of pressure iiuid fromlsaid .pressure "actuated l mernluen and meansffonnecting said distributor` Aito saidplung'er lwith.

foxfs'ynch'fonizedfopera:

4. In'a loading anidunloadin'g meelianisrr'i'kfi'orpumps, the combination with apuinp including cylinders, plungers therein, intake valves for said cylinders, of pressure actuated means for holding said' intake valves opento unload the pump and movable out of valve holding position to permit loading of the pump, valves controlling the delivery of pressure fluid to said pressure actuated means, a distributor' including an actuating cam, means actuated bysald cam for controlling operation of said valves, and means for operating said cam` in synchronism with the pump plungers.

5. In a loading and unloading mechanism for pumps, the .combination with a pump including cylinders, plungers therein, and intake valves for said cylinders, of pressure actuated means for holding said intake valves open to unload the pump and movable out of valve holding position to permit loading of the pump, valves controlling l the delivery of pressure iiuid to said pressure actuated means, a distributor including an actuating cam, means actuated by said cam for controlling operation of said valves, a crank shaft for operating said pump plungers, and means for rotating said cam connected to said crank shaft whereby said cam will be operated in synchronism with the pump plungers for timing the valve operating operations of said pressure actuated members.

6. In a loading and unloadingmechanismior I, pumps, the combination with a pump including cylinders,'plungers therein, and intake valves for said cylinders, of pressure actuated means for holding said intake valves open to unload the pump and movable out of valve holding position,

to permit loading of the pump, valves controlling the delivery of pressure fluid to vsaid pressure actuated means, solenoids for operating said..v

valves, a distributor including a cam, switches actuated by the cam for controlling energizing of said solenoids, a crank shaft for operating saidv pump plungers, and means for rotating said cam connected to said crank shaft for rotating the cam in synchronism with movement of the pump plungers.

7. In a pump loading and unloading mecha-- nism, the combination with a -pump including a cylinder' and a reciprocating plunger therein, of a valve for controlling the loading and unload ing of the cylinder, a pressure actuated member for operating said valve, a valve controlling the delivery of pressure iiuid to said pressure actuated means, a distributor including a cam, means actuated by said cam for controlling operation of said control valve, and means for operating said cam in synchronism with movement of said valves, a distributor including a cam, means for rotating said cam, switches carried by said distributor for controlling energizing of said solenoids, and means for moving saidcam inone direction to operate the switches for energizing said solenoids and in an opposite direction to operate the switches to de-energize the solenoids.

9. In a loading and unloading mechanism for pumps, the combination with a pump including cylinders, plungers therein, and intake valves pump and movable out of valve holding position to permit loading of the pump, valves controlling the delivery of pressure fluid to said pressure actuated means, solenoids for operating said valves, a distributor including a cam, means for rotating said cam, switchescarried by said distributor for controlling energizing'of said solenoids, means for moving said cam in one direction to operate the switches for energizing said solenoids and in an opposite direction to operate the switches to de-energize the solenoids, a crank shaft for operating said pump plungers, said cam rotating means connected to said crank shaft for rotating the camc in synchronism with the crank shaft.

10. In a loading and unloading mechanism for pumps, the combination with a pump including cylinders, plungers therein, and intake valves for said cylinders, of pressure ac tuated means for holding said intake valves open to.unload the pump and movable out of valve holding position to permit loading of the pump, valves controlling the delivery of pressure uidto said pressure actuated means, solenoids for operating said valves, a distributor including a cam, means for rotating said cam, switches carried by said distributor for controlling energizing 'of said solenoids, a solenoid for moving said cam into switch actuating position to load the pump upon energizing thereof, and means for moving the cam in a reverse direction upon de-energizing of the cam moving solenoid to actuate the switches to unload the pump.

11. In a loading and unloading niechanism for pumps, the combination with a pump including cylinders, plungers therein, and intake valves for said cylinders, of pressure actuated means for holding said intake valves open to unload the pump and movable out of valve holding position in a reverse direction upon de-energizing of the cam actuating solenoid to actuate said switches to unload the pump, and means for rotating said cam in synchronism with the movement of the pump plungers whereby the pump will be loaded and unloaded in synchronism with movement of the pump plungers.

12. In a pump loading 'and unloading mechanism, in combination with a pump including a cylinder and a reciprocatingplunger therein, a crank shaft for reciprocating said plunger, a suc.. tion valve for said cylinder, obstruction means for movement into or out of engagement with said suction valve to unload or load the pump, electrically operated means controlling movement of said obstruction means, a control member controlling energizing of said electrically operated means, and means connecting said control member and chank shaft for timing the operation of said obstruction means, whereby it will only be operated at predetermined points during the suction stroke of said plunger.

13. In a pump loading and unloading mechanism, in combination with a pump including a cylinder and a reciprocating plunger therein, a

crank shaft for reciprocating said plunger, a suction valve for said cylinder, obstruction means for movement into or out of engagement with said suction valve to unload or load the pump,

electrically operated means controlling movement of said obstruction means, a control member, said control member including an actuating cam for controlling energizing of said electrically' operated means, means for rotating said cam in cylinder and ja reciprocating plunger therein, a

livery, of pressure fluid to said pressure actuated means, solenoids for operating said valves, a discrank shaft for reciprocating said plunger, a

suction valve for said cylinder, obstruction means for movement into or out of engagement with said suction valve to unload or load the pump, electrically operated means controlling move# ment of said obstruction means, a control member, said control member including an actuating cam for controlling energizing of said electrically operated means, means for rotating said cam in synchronism with rotation of said crank shaft, said cam constructed and arranged whereby energizing and de-energizing of said electrical control means vwill only occur at predetermined points during the suction stroke of said plunger, means for moving said cam in o ne direction whereby the electrical means will be energized,

means for removing the obstruction means from engagement with the suction valve upon energizing of the electrical means, said cam movable in an opposite direction to de-energize the electrical means, and means for moving the obstruction means into engagement with the suction valve upon de-energizingV of the electrical means.

15. In a loading and unloading mechanism for pumps, the combination with a pump including cylinders and plungers therein, of pressure actuated means for controlling loading land unloading of the pump, valves controlling the de- 45 load the plnnp. l

tributor includinga cam, means for rotating said cam, switches carried by said distributor for controlling energizing of said solenoids, means for moving said cam in one direction to operate the switches for energizing said solenoids and in an opposite direction to de-energize the solenoids, and. mechanical means connecting said cam and plungers for operating the cams in syn-l chronism with the plungers.

16. In a loading and unloading Amechanism for pumps, the combination with a pump including cylinders and plungers therein, of pressure actuated means for controlling the loading and unloading of the pump, valves controllingthe delivery of pressure fluid to said pressure actuated means, solenoids for operating said valves, a distributor including a cam, means for rotating said cam, switches carried by said distributor 'for controlling energizing of the solenoids, a

solenoid for moving said cam into switch actuating position to load the pump upon energizing thereof, and means operative upon de-energizing A obstruction means will be operated only at predetermined points during the suction stroke of said plungers,` and means operative upon de-energizingv of said electrically operated means to un- NELsoN-E. BRIGHAM JOSEPH E.. HoLvEcK. 

